Nobody knows for sure...God is just the easy way out of the most difficult question ever known to exist to mankind. Science knows to a point the mechanics...but in reality the Big Bang cancels out what happened before the Big Bang. We can only turn back the clocks so far before scientists say" crap...more thinking!". They do see and can hear the "echoing" of what happened...but nobody was there. In the end, science is more believable then magic from a deity.
The biggest question of all is what caused the big bang, we do know that it happened but before that?... It stands to reason that life is a whole lot more complicated than we think. There are three types of information, things we know, things we know that we don't know and things we don't know that we don't know. The last being of course the more frightening and the true answer to your question.
God is the creator of all things, when He created Adam and Eve they were created to live forever. Sin is what brought about death, but through the death and resurrection of Jesus Christ if we accept Him as our personal Savior we are redeemed.
It currently can't be explained. People like to use things that can't yet be explained as proof of a God, but whatever. It's just like us humans to create something in order to provide a certain level of "understanding".
Not every effect has to have a cause. On the quantum level, everything you know about physics disappears. Quantum particles come and go as they please, leaving existence and then reappearing. This goes against physics, of course. And besides that, quantum particles are both a particle, and a ray, at the same time. Which goes not only against physics, but against logical thinking as well.
All praise is due to Allah, Who created the heavens and the earth and made the darkness and the light; yet those who disbelieve set up equals with their Lord. He it is Who created you from clay, then He decreed a term; and there is a term named with Him; still you doubt. And He is Allah in the heavens and in the earth; He knows your secret (thoughts) and your open (words), and He knows what you earn. And there does not come to them any communication of the communications of their Lord but they turn aside from it So they have indeed rejected the truth when it came to them; therefore the truth of what they mocked at will shine upon them. Do they not consider how many a generation We have destroyed before them, whom We had established in the earth as We have not established you, and We sent the clouds pouring rain on them in abundance, and We made the rivers to flow beneath them, then We destroyed them on account of their faults and raised up after them another generation. And if We had sent to you a writing on a paper, then they had touched it with their hands, certainly those who disbelieve would have said: This is nothing but clear enchantment. And they say: Why has not an angel been sent down to him? And had We sent down an angel, the matter would have certainly been decided and then they would not have been respited. And if We had made him angel, We would certainly have made him a man, and We would certainly have made confused to them what they make confused. And certainly apostles before you were mocked at, but that which they mocked at encompassed the scoffers among them. Say: Travel in the land, then see what was the end of the rejecters.
The universe is larger than humans can readily comprehend and contains many objects too small for humans to see. Whatever caused the universe had to cause a gigantic mass of matter and/or energy, composed of mere particles, to come into existence. Therefore, the cause must be a very powerful, immaterial, being as the uncaused cause. Who we call God.